package org.ad.crypto;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.spec.SecretKeySpec;
  
/*** 
 * @author iWei
 * @date 2013-8-30
 * 
 */  
public class FileDES {
	
	/**
	 * 加密解密的key 
	 */
	private Key mKey;
	
	/**
	 * 解密的密码 
	 */
	private Cipher mDecryptCipher;
	
	/**
	 * 加密的密码 
	 */
	private Cipher mEncryptCipher;

	public FileDES(String key) throws Exception {
		initKey(key);
		initCipher();
	}
      
    /** 
     * 创建一个加密解密的key 
     * @param keyRule  
     */  
    public void initKey(String keyRule) {  
        byte[] keyByte = keyRule.getBytes();  
        // 创建一个空的八位数组,默认情况下为0   
        byte[] byteTemp = new byte[8];  
        // 将用户指定的规则转换成八位数组   
        for (int i = 0; i < byteTemp.length && i < keyByte.length; i++) {  
            byteTemp[i] = keyByte[i];  
        }  
        mKey = new SecretKeySpec(byteTemp, "DES");  
    }  
      
    /*** 
     * 初始化加载密码 
     * @throws Exception 
     */  
	private void initCipher() throws Exception {  
        mEncryptCipher = Cipher.getInstance("DES");  
        mEncryptCipher.init(Cipher.ENCRYPT_MODE, mKey);  
          
        mDecryptCipher = Cipher.getInstance("DES");  
        mDecryptCipher.init(Cipher.DECRYPT_MODE, mKey);  
    }  
      
    /** 
     * 加密文件 
     * @param in 
     * @param savePath 加密后保存的位置 
     */  
	public void doEncryptFile(InputStream in, String savePath) {  
		if (in == null) {
			System.out.println("inputstream is null");
			return;
		} 
        try {  
            CipherInputStream cin = new CipherInputStream(in, mEncryptCipher);  
            OutputStream os = new FileOutputStream(savePath);  
            byte[] bytes = new byte[1024];  
            int len = -1;  
			while ((len = cin.read(bytes)) > 0) {
				os.write(bytes, 0, len);
				os.flush();
			} 
            os.close();  
            cin.close();  
            in.close();  
            System.out.println("加密成功");  
		} catch (Exception e) {
			System.out.println("加密失败");
			e.printStackTrace();
		} 
    }  
      
    /** 
     * 加密文件 
     * @param filePath 需要加密的文件路径 
     * @param savePath 加密后保存的位置 
     * @throws FileNotFoundException  
     */  
    public void doEncryptFile(String filePath, String savePath) throws FileNotFoundException {  
        doEncryptFile(new FileInputStream(filePath), savePath);  
    }  
      
      
    /** 
     * 解密文件 
     * @param in 
     */  
	public void doDecryptFile(InputStream in) {
		if (in == null) {
			System.out.println("inputstream is null");
			return;
		} 
        try {  
            CipherInputStream cin = new CipherInputStream(in, mDecryptCipher);  
            BufferedReader reader = new BufferedReader(new InputStreamReader(cin)) ;  
            String line = null;  
			while ((line = reader.readLine()) != null) {
				System.out.println(line);
			} 
            reader.close();  
            cin.close();  
            in.close();  
            System.out.println("解密成功");  
        } catch (Exception e) {  
            System.out.println("解密失败");  
            e.printStackTrace();  
        }  
    }
	
    /** 
     * 解密文件 
     * @param filePath  文件路径 
     * @throws Exception 
     */  
	public void doDecryptFile(String filePath) throws Exception {
        doDecryptFile(new FileInputStream(filePath));  
    }  
      
      
    public static void main(String[] args)throws Exception {  
        FileDES fileDES = new FileDES("spring.sky");  
        fileDES.doEncryptFile("d:/a.txt", "d:/b");  //加密   
        fileDES.doDecryptFile("d:/b"); //解密   
    }  
      
}  